1. Field of the Invention
This invention relates to improved internal fixation means used in surgical procedures to treat fractured bones, pending fractures of bones, non-unions, arthritis, as well as any other procedure in which an attempt is made to surgically fuse two or more bones. More particularly, this invention relates to an orthopedic surgical implant and its method of use for stabilizing the relative position between a bone having a medullary canal and an adjoining bone or bone section.
2. Description of the Related Art
In recent years, both solid and tubular, metal rods or intramedullary nails have gradually gained importance in orthopedic surgery. They have in many situations become the standard surgical implant for stabilizing fractures or pending fractures in large tubular bones, such as the femur (thigh bone), tibia (leg bone) or humerus (upper arm bone).
The shape and configuration of such intramedullary nails has been a topic of much inventive effort. From initially circular or almost circular cross-sections, these nails have, in order to minimize the damage done to the bone during their placement in the body, come to be designed such that their cross-sections correspond to the anatomy of the medullary canals in which they are to be used.
For example, for the humerus bone, in which the medullary canal is not round along its entire length but is in fact flat and thin in the distal part, a nail with a flattened cross-section for its distal end has been developed. See U.S. Pat. No. 6,231,576.
In order to avoid the rotation of bone fragments and their shortening in multifragmented fractures, these nails have come to be used with various accessories, such as anchoring screws and other elongated, blade-like elements, that pass through holes in such nails and attach to the various bone fragments. See U.S. Pat. Nos. 5,928,235, 6,077,264, 6,235,031 and 5,562,667 for examples of such elements and their methods of use for stabilizing fractures of the neck of the femur.
Despite the extensive development of such intramedullary nails and accessories, it was recognized that they continued to exhibit certain disadvantages. For example, their designs were such that: (1) they often offered only minimal flexibility in addressing situations in which the bones or bone fragments to be stabilized have unique geometries or orientations, (2) they often involved relatively complex designs which tended to increase their costs of manufacture, and (3) their uses were confined primarily to the treatment of fractures and pending fractures in individual large, tubular bones and for limited fusions of the ankle and knee—they had also been used in situations to stabilize one or several bones, but (4) they did not provide stability in all three, orthogonal planes of motion.
In an attempt to address these disadvantages, the modular, blade-rod intramedullary fixation device of U.S. Pat. No. 6,572,620 was developed by the present inventors. See FIGS. 1-3.
FIG. 1 depicts the situation in which this intramedullary fixation device is being used to stabilize the position of the shin bone (tibia) relative to the adjoining ankle (talus) and heel (calcaneus) bones. The device is seen to consist of an intramedullary nail or rod that has been inserted through the bottom of the foot and into the medullary canal of the tibia. A threaded bore extends from the nail's proximate end and along a specified portion of its longitudinal axis. See FIG. 2.
An elongated blade is seen to have been driven through the adjoining ankle bone whose position is to be fixed relative to that of the tibia. A passageway adjacent the blade's proximate end extends between its top and bottom surfaces, thereby providing a passage through which a screw may be passed in order to lock the blade and nail together. When the nail's design is such that its proximate end section is not perpendicular to its longitudinal axis, a washer is used to align the longitudinal axes of the nail and the screw.
FIG. 3 provides a perspective view of an insertion jig or alignment apparatus that is used to locate and precisely position, within the bones to-be-treated, the nail and blade of this device. It consists of a base portion with a seat section upon which the to-be-inserted nail and washer may be aligned and positioned prior to insertion. It also includes a detachable, blade alignment section that has an orifice through which the blade is passed for insertion into the targeted bone. Into this orifice can also be inserted a guidewire adapter which contains an orifice in which a guide pin can be placed and then fed into the precise position where the blade is to-be-inserted into the bone. The alignment apparatus also has a tower section in which are located additional holes which serve to locate and align with the openings that are situated along the length of the nail. These holes are used to help fasten additional support screws or other attachment means for providing further stabilization means for the nail.
Despite improving upon the prior technology, it has been recognized that the intramedullary fixation device of U.S. Pat. No. 6,572,620 still has certain drawbacks. For example, it can encounter situations in which the shapes of the bones, whose positions it is meant to stabilize, make insertion of the intramedullary rod and blade exceedingly challenging.
This situation is due, in part, to the need to partially or completely detach the insertion jig from the rod so as to make room beneath the rod to allow the blade to pass below the rod. This introduces the potential for instability between the bones and for loss of alignment of the blade relative to the rod, loss of alignment of the rod relative to the foot, and loss of alignment of those bones held by the rod and the blade. Additional efforts to stabilize the bones without the use of the jig can necessitate other procedural steps that result in increased surgical trauma for the patient.
Thus, there still exists a continuing need for the development of new and improved intramedullary fixation devices.
3. Objects and Advantages
Recognizing the need for the development of improved internal fixation means that are used in surgical procedures to treat fractured bones, etc., the present invention is generally directed to satisfying the needs set forth above and overcoming the disadvantages identified with prior art devices.
It is an object of the present invention to provide an improved intramedullary fixation device and method that offers maximum flexibility in addressing situations in which the bones or bone fragments to be stabilized have unique geometries or orientations.
It is another object of the present invention to provide an improved intramedullary fixation device that can be used without having to decouple its component parts during their surgical insertion; thereby preventing the possibility that the bones which have been aligned for fixation might fall out of alignment.
It is yet another object of the present invention to provide an improved intramedullary fixation device and method that can be used for treating situations other than just the treatment of fractures and pending fractures in individual large, tubular bones. For example, to treat the situation in which the position of two or more adjoining bones are stabilized in order to allow and promote surgical fusion, or arthrodesis, of these bones. Some examples of such non-fracture, clinical applications include arthritis, infection, neuropathy and deformity.
It is a further object of the present invention to provide a method and device for providing stabilization of the relative position between two or more bones that may or may not share adjacent surfaces (e.g., the tibia, talus and calcaneus).
It is a still further object of the present invention to provide a device and method that will advance the utility of intramedullary nails in orthopedic medicine.
These and other objects and advantages of the present invention will become readily apparent as the invention is better understood by reference to the accompanying drawings and the detailed description that follows.